Augsburg have signed South Korea international Koo Ja-Cheol from Mainz on a two-year contract.
Koo, now 26, scored eight goals in 36 games for Augsburg while on loan from Wolfsburg during the 2012-13 season and returns on a permanent basis.
"After he left Augsburg we remained in regular contact," director of sport Stefan Reuter told his club's official website.
"When this opportunity to sign him arose, we seized it.
"He knows the club, the surroundings, as well as the coach and the team, so Koo is not going to need much time to settle here at Augsburg."
Koo struggled a lot with injuries during his time with both Wolfsburg and Mainz and will be hoping to endure less misfortune back in Bavaria.
"I was always happy at Augsburg and now I have the feeling that I am coming home," he said.
"It's great that this transfer went through at such short notice. Now I'm looking forward to joining this club and I would like to help the team reach our goals in the Bundesliga, the DFB-Pokal and the Europa League."
Augsburg have picked up just one point from their first three Bundesliga games of the season.